Ansible

Basic information

• Official Website: https://www.ansible.com/

• License: GNU GPL v3

• Installed on: Apolo II, Cronos

Preliminaries

Information contained within this section elucidate the basic usage of ansible’s common features (i.e. those which, at the very least, allow it to perform simple tasks).

• 1. Inventory
• 2. Group variables
• 3. Modules
• 4. Playbooks
• 5. Roles
• 6. Vault (Encryption)
  • 6.1. Create encrypted files
  • 6.2. Encrypt files
  • 6.3. Encrypt variables as a string
  • 6.4. Edit encrypted files
  • 6.5. View encrypted file
  • 6.6. View encrypted string
  • 6.7. Decrypt files
  • 6.8. Change encryption key
  • 6.9. vault-password script
• 7. Environments

Dynamic control

This section describes mechanisms to control which tasks are to be executed in a particular run.

• 1. Tags
  • 1.1. Inheritance
  • 1.2. Special tags
  • 1.3. Example

Deployment strategy

Ensuring the system’s state remains as desired after deployment requires constant monitoring of configuration files, daemons (services), etc. Bearing this in mind, employing a self-aware architecture—in which tasks are not run once, but repeatedly and their actions are performed based on checking the system state—is a reasonable choice.

To further ease deployment one may find useful to provision a server, or set of servers, by using wrappers triggering ansible’s execution, one-shot playbooks and scripts.

This section proposes an architecture integrating all the abovementioned ideas.

• 1. Overview
• 2. Provisioning logic
  • 2.1. Directory hierarchy
  • 2.2. Ansible launcher
  • 2.3. Scheduled run
• 3. bootstrap
• 4. Example

Tips and tricks

• 1. Installation of multiple packages
• 2. User account creation

Troubleshooting

• 1. Ansible Vault
  • 1.1. Newer pycrypto required
• 2. Playbooks
  • 2.1. Invalid user password

Authors

• Tomás Felipe Llano-Rios <tllanos@eafit.edu.co>